A Predictive Model for Respiratory Failure and Determining the Risk Factors of Prolonged Mechanical Ventilation in Children with Guillain-Barre Syndrome

Objective: Determining the predictors of respiratory failure and duration of intubation in children with Guillain-Barre syndrome (GBS). Materials & Methods: Children diagnosed with GBS at Tabriz Children’s Hospital were studied. Factors associated with and influencing respiratory failure as well as the duration of intubation were determined using both univariate and multiple analyses. Results: Overall, 324 children were enrolled in the study, 54.0% of whom were males. Thirty-one (9.6%) patients underwent mechanical ventilation, the patients under 5 years old were more prone to the requirement of mechanical ventilation (11.3% vs. 6.9%). Cases hospitalized in winter were more likely to need ventilation compared to those hospitalized in spring (OR =7.00; 95% CI:1.51-32.53). Also, autonomic involvement (OR=8.88, 95% CI:4.03-19.58; p<0.001) and cranial nerves involvement (OR=9.88, 95% CI:3.68 - 26.52; p<0.001) emerged as risk factors for mechanical ventilation requirement. Overall, 16.1% of patients with axonal electrophysiologic pattern required mechanical ventilation compared to 7.4% of those with demyelinating type (OR:2.15, 95% CI: 1.01-4.69). In univariate analysis, the only variable that showed a correlation with the duration of intubation was axonal electrophysiologic pattern (p= 0.028). Conclusion: Approximately, 10% of the patients required mechanical ventilation. Season, cranial nerve involvement, autonomic dysfunction and electrophysiologic pattern were the most important variables in predicting respiratory failure and duration of mechanical ventilation.

Unfortunately, 60% of patients who have been intubated and undergone MV were diagnosed with a major problem such as pneumonia, pulmonary embolism, sepsis, and gastrointestinal bleeding.
In addition, the risk of aspiration pneumonia may increase in a patient with delayed intubation (6,8).
Prediction of early MV in children with GBS, for the avoidance of aspiration, pneumonia, respiratory distress, septicemia and admission to ICU is necessary. Early MV may be helpful for better management and reduced complications and mortalities, and in turn, improved outcomes in such patients (6)(7)(8).
Also, mortality rate in patients with GBS whom have undergone MV varied from 8.3 to 20% (9), and the duration of MV in these patients ranges from a few days to even longer than several months. Because prolonged MV may lead to several complications such as damage to vocal cords and recurrent laryngeal nerves, if expected MV duration is more than two weeks (prolonged MV), early tracheostomy should be considered for the prevention of such damages.
On the other hand, prediction of prolonged MV can curtail unnecessary early tracheostomy that causes infections, esophageal perforation, tracheal stenosis and scar (10). Previous studies on adult patients showed various risk factors for MV and respiratory insufficiency in this group such as rapid progressive weakness, cranial nerves deficits and areflexia (6).
To the best of our knowledge, there are limited studies with large sample sizes investigating the predictors of respiratory failure in childhood GBS.
Thus, we aimed to perform a comprehensive evaluation of the predictors of respiratory failure.
We sought to develop a model for the prediction of respiratory insufficiency and the risk factors for prolonged MV in children with GBS ass a guide for decision-making on early intubation to reduce the associated major complications and improve outcomes in these patients.
Based on the aim of this study, the patients were compared according to the need for mechanical ventilation and duration of intubation.

Statistical Analysis
For analysis, SPSS version 16.0 was used. In the descriptive statistics section, mean and standard deviation were used for quantitative variables and frequency and percentage was used for qualitative variables. The study factors were compared between those who received mechanical ventilation and those who did not by using Chi-square test or, if necessary, using Fisher's exact test. Then, the variables that were significant at the level of 0.2 were considered as potential factors in predicting the need for ventilation and were entered into a multiple logistic regression model. At this stage, odds ratio and confidence interval for the odds ratio of all the variables were calculated and reported.
To explore difference in mechanical ventilation

Results
In this study, 324 patients admitted to Tabriz Children Hospital with GBS diagnosis were enrolled, of whom 175 (54.0%) were male. Their mean age was 5.13 ± 3.66 years (6 months to 16 years old).
The results of baseline characteristics showed that GBS was more prevalent in children under the age of 5 years and in summer. Also, upper respiratory tract infection was the most commonly reported illness that occurred before the onset of paralysis.
Thirty-one (9.6%) patients underwent mechanical ventilation, mean duration of intubation was 20.75 ± 21.25 days and mortality rate was 1.5%. Although age and mechanical ventilation association did not reach statistical significance, the patients under 5 years old were more prone to need for mechanical ventilation (11.3% vs. 6.9%). The predictors of mechanical ventilation requirement were seasonal prevalence (16.5% in winter vs. 2.8% in spring; OR: 7.00, 1.51 -32.53, p=0.04).
In addition, children with autonomic nervous system involvement were significantly ( Table 1).
The most common complication was pneumonia which was found in 17 (5.2%) patients. GI bleeding was seen in 8 (2.5 %) patients. Other complications were found in 6 patients (collapse -5 and atelectasis -1), and pneumonia and collapse were reported in eight (2.5%) patients simultaneously.

Anticipating Mechanical Ventilation Requirement
To identify variables predicting the need for mechanical ventilation, variables that were significant in univariate analysis at the level of 0. The results presented in Table 2 show that using the three independent variables included in this model

Duration of Mechanical Ventilation
The results shown in Table 3     There are two important issues in the field of GBS management, that is, short-term poor prognosis (acute respiratory failure and death) and long-term poor prognosis (delay in independent walking ability). Differences in mechanical ventilation rate could be due to different study populationss, pathogens, supportive care, and the decision to start artificial ventilation (18).
It seems that weakness in facial, oropharyngeal, retropharyngeal, and respiratory muscles in addition to secondary complications such as pneumonia or alveolar collapse are responsible for respiratory failure in GBS (19,20). GBS may lead to bulbar paralysis, ophthalmoplegia, and lingual Iran J Child Neurol. Summer 2020 Vol. 14 No. 3 muscles weakness. Facial and shoulder muscle paralysis in accordance with dysphagia are the risk factors for respiratory failure (21). In the present study, the most involved (43.3%) cranial nerves were 9 and 10.
Younger age of the disease was a risk factor for respiratory failure (18,21), in this study patients under 5 years old were more prone to require mechanical ventilation.
We found no significant relationship between preceding infection and respiratory failure.
However, some studies suggested that if the duration between preceding infection and weakness onset was shorter than 8 days, respiratory failure is probable (21) Autonomic nervous system involvement is were not assessed in this cross-sectional study, and we could not statistically analyze AMSAN subtype separately due to the limited number of these cases.

In conclusion
Based on the findings of this study conducted